CHAPTER 5: SETTINGS GROUPED ELEMENTSL30 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 5-2395The positive-sequence restraint allows for more sensitive settings by counterbalancing spurious negative-sequencecurrents resulting from• System unbalances under heavy load conditions• Transformation errors of current transformers (CTs) during three-phase faults• Fault inception and switch-off transients during three-phase faultsThe positive-sequence restraint must be considered when testing for pickup accuracy and response time (multiple ofpickup). The operating quantity depends on how the test currents are injected into the relay (single-phase injection:Iop = 0.2917 x Iinjected ; three-phase injection, opposite rotation: Iop = I injected ).Figure 5-121: Negative sequence IOC1 logic5.7.8 Breaker failure (ANSI 50BF)SETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) BREAKER FAILURE BREAKER FAILURE 1(2) BREAKER FAILURE 1 BF1 FUNCTION:DisabledRange: Disabled, Enabled BF1 MODE:3-PoleRange: 3-Pole, 1-Pole BF1 SOURCE:SRC 1Range: SRC 1, SRC 2 BF1 USE AMP SUPV:YesRange: Yes, No BF1 USE SEAL-IN:YesRange: Yes, No BF1 3-POLE INITIATE:OffRange: FlexLogic operand BF1 BLOCK:OffRange: FlexLogic operand BF1 RETRIP PICKUPDELAY: 0.033 sRange: 0.000 to 65.535 s in steps of 0.001 BF1 PH AMP SUPVPICKUP: 1.050 puRange: 0.020 to 30.000 pu in steps of 0.001 BF1 N AMP SUPVPICKUP: 1.050 puRange: 0.020 to 30.000 pu in steps of 0.001 BF1 USE TIMER 1:YesRange: Yes, No
